Investigators say a family friend of the gunman, U.S. Army Spc. Ivan Lopez, told them he was struggling with the deaths of his mother and grandfather.
He shot and killed three soldiers at Fort Hood on Wednesday.
The mother of one of the victims says her son was trying to calm down Lopez when he was shot several times.
Investigators say Lopez got into an argument with someone right before the shooting, and a senior officer at Fort Hood says his mental health was not the main factor in the shooting.
Fort Hood's commander said doctors had evaluated Lopez, looking for signs of Post-Traumatic Stress Disorder.
Even though Lopez didn't see combat during his deployment, some mental health professionals say just being there can cause problems for some people.
After the shootings Fort Hood, Tulsa mental health professionals are reaching out to veterans who may need their services.
"Often times they don't want to reach out for treatment," Carla Tanner of the Community Service Council said. "There's a lot of stigma still involved in treatment and we just try to outreach as many ways as we can."
In the past two years, Carla Tanner's group has trained more than 200 area professionals to treat soldiers with PTSD symptoms.
Tanner said soldiers like the Fort Hood shooter can suffer from a disorder similar to PTSD.
She says a moral injury to a soldier in the field can cause distress.
"When they return home they have difficulty being involved... whether they carried a weapon or not, seeing the devastation that occurred," Tanner said.
According to Oklahoma Watch, veterans in the Sooner State are killing themselves at twice the rate of their civilian counterparts.
"My heart goes out to families that are directly... horrible, horrible thing," U.S. Army Physician Chad Edwards said.
Edwards said there is a solution to treat soldiers who suffer from traumatic brain injuries.
He strongly believes the oxygen therapy in a hypobaric chamber can help people suffering from these post-combat illnesses.
Edwards says the therapy is tied up in red tape and lawmakers are trying to make it usable in Oklahoma.
"Anyone with a potential brain injury, I think they need to be thoroughly evaluated with a physical exam and histories and things like that, and then something like hyperbaroic oxygen therapy is really an excellent tool that has the potential to make a significant and profound impact," he said.
Treatment for veterans is available through Veterans Affairs. More information can be found on the agency's website.
The easiest way to get in touch with a mental health professional in Tulsa is to dial 211.